Project Summary Nationwide, Mexican-American adults over age 30 have the highest prevalence of periodontal disease of all racial/ethnic groups (67% vs. 43% fornon-Hispanic Whites)(Eke, Dye et al. 2015). Poor oral hygiene is one risk factor for this common, preventable disease. However, few interventions focus on improving oral hygiene in this high-risk group, many of whom are also low-income and lack access to dental care. Social support has been targeted successfully in social and behavioral interventions to improve dietary behaviors, physical activity, and chronic disease management among Mexican-origin adults, but it has not been studied extensively in an oral health context. In addition, the role of social support differs for men and women with other health behaviors, supporting the need to study differences between men and women. This study addresses these gaps by developing a bilingual (English/Spanish) oral health behavior-specific social support scale for use in future intervention research. Developing such a measure will enable more precise assessment of the role and perceived impact of different sources and types of social support on daily hygiene behavior, dental care utilization, and oral health outcomes. Our experienced, multi-disciplinary team proposes a two-phase mixed methods study that will: 1) qualitatively explore the relevant social influences on oral health behavior for lower income Mexican-origin young adult men and women to understand structural and functional aspects of social support; 2) develop and pilot test an oral health behavior-specific social support scale, and 3) quantitatively assess the scale?s psychometric properties and association with oral health status and behavior. Phase I proposes semi-structured interviews with 25-40 men and 25-40 women from the target population of Mexican- origin young adults, to explore dimensions of social support in an oral health context as part of scale item generation and refinement. Cognitive interviews will be conducted to assess scale content and understanding of item and response option wording and order of the draft scale with 40 different adults from the target population, before it is piloted with 200 adults. Phase II will quantitatively validate the scale. Surveys will be conducted with 500 men and women, and a subset of >250 will also receive a dental exam. Phase II analysis will include cluster and factor analysis of the new social support scale, calculate the Cronbach?s alpha to assess internal consistency, and assess scale and subscale validity (content, face, construct, concurrent, divergent, and discriminant validity) and reliability. Sex-stratified analyses will examine associations with self-reported oral hygiene behavior (brushing, flossing, rinsing), dental care utilization, multiple self-rated oral health status indices, and clinically-assessed oral health status (tooth loss; caries; periodontal disease). This study will yield a culturally-sensitive social support scale that will advance understanding of potential pathways through which social relationships affect oral health behavior and outcomes for young adults of Mexican-origin, at high risk for oral disease, findings important for future theory-informed, evidence-based randomized controlled trials.